561 research outputs found

    Humerus shaft fracture complicated by radial nerve palsy: Is surgical exploration necessary?

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    Fractures of the humerus shaft often are complicated by radial nerve palsy. Controversy still exists in the treatment that includes clinical observation and eventually late surgical exploration or early surgical exploration. Algorithms have been proposed to provide recommendations with regard to management of the injuries. However, advantages and disadvantages are associated with each of these algorithms. The aim of this study was to analyze the indications of each treatment options and facilitate the surgeon in choosing the conduct for each lesion, proposing our own algorithm

    Scapholunate interosseous ligament injury in professional volleyball players

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    Injuries to the scapholunate interosseous ligament (SLIL) are the most common cause of carpal instability. A SLIL injury typically follows a fall on an outstretched hand, with the wrist in hyperextension, ulnar deviation and intercarpal supination. We hypothesize that repetitive axial loading on the wrist in hyperextension, during the reception and digging motions of volleyball, can lead to functional overloading of the SLIL. To identify patients and to determine the clinical history and surgical treatment performed, we analyzed hospital records, X-rays, electronic databases containing all the operations performed, and image files (including before and after surgery and follow-up). We identified three SLIL injury cases in national volleyball team players, also at the libero position, who were treated at our clinic between 2007 and 2013 for scapholunate instability. Open reduction and Berger capsulodesis was performed in all cases. At a mean follow-up of 3 years (range, 22â50 months), the mean pain level on VAS was 0.3 (range, 0â1) at rest and 1.7 (range 1â2) during sport activities. The mean DASH score was 4 (range 2â5). The mean wrist flexion was 60° (range 55â70°) and extension was 80° (range 75â85°). Given the greater susceptibility of these players for developing a SLIL injury, a high index of suspicion is needed when managing athletes presenting with wrist pain or instability

    Optical frequency standard with ultra-cold strontium atoms

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    The dependence of test-mass thermal noises on beam shape in gravitational-wave interferometers

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    In second-generation, ground-based interferometric gravitational-wave detectors such as Advanced LIGO, the dominant noise at frequencies f40f \sim 40 Hz to 200\sim 200 Hz is expected to be due to thermal fluctuations in the mirrors' substrates and coatings which induce random fluctuations in the shape of the mirror face. The laser-light beam averages over these fluctuations; the larger the beam and the flatter its light-power distribution, the better the averaging and the lower the resulting thermal noise. In semi-infinite mirrors, scaling laws for the influence of beam shape on the four dominant types of thermal noise (coating Brownian, coating thermoelastic, substrate Brownian, and substrate thermoelastic) have been suggested by various researchers and derived with varying degrees of rigour. Because these scaling laws are important tools for current research on optimizing the beam shape, it is important to firm up our understanding of them. This paper (1) gives a summary of the prior work and of gaps in the prior analyses, (2) gives a unified and rigorous derivation of all four scaling laws, and (3) explores, relying on work by J. Agresti, deviations from the scaling laws due to finite mirror size.Comment: 25 pages, 10 figures, submitted to Class. Quantum Gra

    Generation of a flat-top laser beam for gravitational wave detectors by means of a nonspherical Fabry-Perot resonator

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    We have tested a new kind of Fabry-Perot long-baseline optical resonator proposed to reduce the thermal noise sensitivity of gravitational wave interferometric detectors--the "mesa beam" cavity--whose flat top beam shape is achieved by means of an aspherical end mirror. We present the fundamental mode intensity pattern for this cavity and its distortion due to surface imperfections and tilt misalignments, and contrast the higher order mode patterns to the Gauss-Laguerre modes of a spherical mirror cavity. We discuss the effects of mirror tilts on cavity alignment and locking and present measurements of the mesa beam tilt sensitivity
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